Treatment of paper and board



Patented Mei-s12, 194a uNrrEu STATES TREATMENT- OF PAPER'AND BOARD Sidney Musher, New York, N. Y., assignor to Musher Foundation Incorporated, New York, N. Y., a corporation of New York No Drawing. Application March 29, 1939, Serial No. 264,735

9 claims.

This invention relates tothe treatment of paper packaging materials with antioxygenic agents in order to retard oxidative deterioration thereof and also to retard the deterioration of packaged products. g

' Particularlywhere pine is used as the stock in the manufacture of paper and board, the oxidizable oils contained therein make that paper or board very subject to deterioration, whereby obm jectionable board and other oxidation odors de- Another object is the retardation of oxidation in packaged products where such papers and boards are used for the wrapping of oxidizable materials.

Still further objects and advantages willappear from the more detailed description set forth below, it being understood, however, that this more detailed description is given by way of illustration and explanation only, and not by way of limitation, since various changes therein may be made 35 by those skilled in the art without departing from the scope and spirit of the present invention.

In accordance with this invention there is applied, preferably as a sizing, finely divided cacao nibs which are preferably roasted and then substantially de-oiled or de-fatted and then powdered or pulverized. This may be done by expressingthe fat out of the cacao nibs, and grinding the residue to a fine mesh, preferably over 50 mesh and applying said powder as a surface sizing for paper, board and similar packaging materials.

' The shells of the cacao nibs which are substantially oil free may also be removed, finely 0 ground and applied in similar fashion.

The finely divided cacao residue apart. from the shells contains less than 30% fat and is not oily in character, most of the oil having been removed during the expressing operation. By

I the term "cacao residue is included both the shells as well as the defatted, finely divided cacao nibs.

It is particularly desirable for the application of the finely divided cacao residue to be made to the paper or board as a surface sizing agent. '5 For example, a mixture may be prepared comprising from 2% to by weight of the finely divided cacao residue in water, and preferably about 8%, subjecting such water containing the finely divided cacao residue to thorough agitation and admixture, and passing the paper or board I through such water bath containing the finely divided cacao residue at the calendar, boxes or between the first drying rolls and the finishing rolls or as part of a tub sizing operation.

A particularly desirable method of application is for the finely divided cacao residue in water suspension to be sprayed or allowed to flow on the moving sheet of paper or board at the wet end of the paper machine and immediately before such paper or board comes in contact with the hot drying rolls.

When the finely divided cacao residue is applied as a tub sizing or at the calendar stacks, to the q extent that the finely divided cacao residue adheres to the surface of the paper or board, and is subsequently dried on the surface of that paper or board during the manufacturing operation, there will be applied approximately from 0.2% by weight to 5% by weight of the finely divided cacao residue against the weight of the paper or board. Where the finely divided cacao residue in water suspension is allowed to flow on or is sprayed on the wet end of the paper machine and on to the sheet of paper as it moves to the heated rolls, there may be applied any desired percentage of the finely divided cacao residue to the paper or" board as the amount that is applied to 'the paper or board may definitely be controlled when applied in this manner. The residue adhering to 40 the surface of the paper or board will not be dependent upon the amount that is picked up by the paper or board as would be the case if it were passing through a bath of the suspended residue.

The papers that may be treated in,this manner include any grade such as parchment, greaseproof, glassine, sulphite, prime or secondary stock boards, etc. Such papers may subsequently be oiled, paramned, waxed or otherwise treated following the application of the finely divided cacao residue thereto.

Particularly where paper is oiled, for example, such oiled paper is normally subject to rapid oxidative deterioration due to thedecomposition or oxidation of the oils contained in that paper.

This presents a serious problem separate from the problem that is presented when such oiled paper is used for the wrapping of fatty meats, for example, where some of the fat leaves the meat and is adsorbed on the surface of the paper and rapidly becomes rancid in contact with that paper.

A 35 pound sulphite paper stock was passed through a bath containing 8% finely divided powdered cacao residue containing 15% total fat and capable of passing through a 70 mesh screen. Said residue was held in suspension in the water using continuous agitation. The paper was passed through that bath at the rate of approximately 10 feet per second. The paper was then dried on drying rolls at about 220 F. There was applied to the paper approximately 0.6% by weight of the finely divided cacao residue against the weight of the paper. That paper was then impregnated with a petrolatum oil to a 40 pound weight. When such paper was placed. into storage and compared in keeping quality with similar oiled paper but without the finely divided cacao residue, it was observed that within a period of approximately 3 months at room temperature off odors developed, whereas in the untreated paper an off odor developed within about 40 days. These papers were also used for the wrapping of hams which were placed into freezer storage. At the close of a 6 month period, the hams wrapped in the treated oiled paper were superior in flavor and showed much less rancidity development than the hams which were wrapped in the untreated paper.

This process is also of value for board to retard the development of the characteristic cardboard odor that develops particularly with the cheaper grades of board.

This process is particularly valuable when applied in pinewood board where the oils normally contained in the pine are subject to such rapid oxidation resulting in very objectionable cardboard and other off odors that readily contaminate products with which it cames intocontact.

In the case of pine wood board, the pine wood is first ground to a fine mesh and put through the usual beater operations. The beater stock consisting in whole or in part of the pine base is then run on to the wet end of the board making machine for the fibres to interlock and the board to form.

The application of the finely divided cacao residue should desirably be made immediately before the board reaches the heated drying rolls so that after the residue has been applied, the board -iTs subjected to a temperature of at least 220 F. and preferably at about 260 F. Board made of ground pine stock treated in this manner is very substantially resistant to deterioration.

It has been observed that where the finely divided cacao residue is applied to the board following the heat treatment and at the very end of the manufacturing operation and where the board is not subsequently subjected to a temperature of as high as about 250 F. for example, retardation of the development of characteristic objectionable board and other off odors is not near- 1y as great as where the residue is applied prior to the high heat treatment at the drying rolls.

Example I] Ground wood made of pine stock was prepared in aqueous suspension containing 70% water and 30% total solids. Samples of this material were prepared as follows:

A. Nothing added; placed in an oven at 260 F.

for 5 minutes.

B. 0.5% by weight of 50 mesh finely divided cacoa residue added and thoroughly mixed in; then placed in an oven at 260 F. for 5 minutes.

C. Nothing added; placed in anoven at 260 F. for 5 minutes; removed and allowed to cool; then added 0.5% by weight of the same finely divided cacao residue and thoroughly mixed in.

These samples were then allowed to remain exposed to air. At the end of 7 days the sample A turned oif. At the end of 12 days sample C turned oif", whereas the sample B did not become off" until after 23 days.

It is not known as to exactly how or why the high heat of the ground wood containing the finely divided cacao residue produces the marked stabilizing action, but it is evident that the high heat is desirable in order for the maximum stabilizing results to be obtained.

Where, in addition, the finely divided cacao residue is added to paper and where that paper is subsequently oiled, the oiling should be conducted at an elevated temperature of at least F. and preferably in excess of 200 F. in order -for the heat to be suflicient to cause the desired reaction to take place.

It is possible for the finely divided cacoa residue to be added to the beaters, but this procedure is normally considered less desirable than where the residue is added as a sizing operation on the surface of the paper or board as above indicated.

It is also possible for the finely divided cacao residue to be added to the paraflin or oil that is applied to the paper, but it has been found that where such addition is made to the paraffin, wax or oil, the presence of the residue in that surface coating reduces moisture protection and makes the paper much more resistant to penetration of moisture than before.

In the packaging of such products as dairy products including ice cream, butter, powdered whole milk, cheese, etc., fats and oils such as lard, oleomargarine, shortening, etc., chocolates, coffee and tea,candies,caramels, cookies, crackers, cakes and other baked goods, etc., whole wheat biscuits, cereals, bacon and other meat products, etc., the treatment as herein indicated will materially improve the keeping quality of those packaged products separate from improving the keeping quality of the paper or board itself.

Example III Glassine paper, after the super-calendering operation was passed through a bath consisting of 10% of a 70 mesh cacao residue in water. The glassine paper was then dried on the drying rolls at about 220 F. There was applied to the glassine paper by this procedure 1.5% by weight of the finely divided cacao residue. A weighed amount of lard was brushed on the surface of this paper and peroxide values were taken at regular'intervals in order to determine the resistance of that paper to rancidity of the fat at its surface.

4 products wrapped in them. Where the pH is Such treated packaging materials may be used for the preparation of paper milk bottles, and even where liquid products such as milk, chocolate milk, orange juice, etc. are packaged, an improvement in the keeping quality of those liquid products is obtained.

The substantially oil free finely divided ground cacao shells may most satisfactorily be utilized for the purposes as outlined herein. The cacao nibs before roasting and de-oiling and after grinding may also be employed but these are much less desirable for the purposes outlined herein than the finely divided cacao residue and cacao shell residue as indicated.

A similar application of the finely divided cacao residue as here indicated may be made not only to papers and cartons or boards, but also to metal containers such as to tin, to cloth containers such as to cloth bags, to cap liners, wooden tubs, etc.

In addition to using these cacao residues, their extracts may also be employed, and particularly those obtained by the use of volatile solvents and most particularly by the use of a water soluble or an alcohol soluble solventand similar products having the formula XOH wherex is hydrogen or a low molecular weight aliphatic group.

The extracts are prepared by immersing the finely divided residues in the solvent, such as ethyl alcohol, using about from 5 to 15 parts of alcohol to each party of residue, agitating for from 5 minutes to one hour at a slightly elevated temperature, filtering out or otherwise removing the alcohol containing the dissolved extracted material, and then removing the alcohol, preferably under reduced pressure, whereby the extract substantially free of solvent remains. These extracts may be applied in a manner analogous to that described above for the residues themselves.

These extracts are. however, not considered as desirable for use in the treatment of paper-and board as are the residues themselves.

The treated paper or board should desirably be adjusted to a pH of between 4 and 6.9, and preferably at a pH of about 5.0 to 8.0 before app y the residues thereto. This pH adjustment greases is highly desirable in order to obtain maximum results in stabilizing the paper or board and above 7.0, the protective eflect normally exerted is very substantially reduced.

This application is a continuation in part of copending application, Serial No. 92,936, filed July 27, 1938.

What I claim is:

l, The method of making antioxygenic paper and board which comprises incorporating with the paper .andboard about between 0.2% and 5% of cacao residue, and then heating to at least about 220 F. p

2. In the method of making antioxygenic paper and board, the steps of providing paper and board having a pH of about between 4 and 6.9,

and then incorporating with the paper and board between about 0.2% and 5% of cacao residue.

3. Antioxygenic paper and board containing the heat reaction products of the reaction between 0.2% and 5% of cacao residue and the' paper and board, said reaction being obtained by heating the paper and board to at least about 220 F.

4. Antiox'yzenic paper and board containing between about 0.2% and 5% of cacao residue a'ndhaving a pH of-between about 4 and 6.9.

5. In the method of making antioxygenic paper and board, the steps of providing paper and board having a pH of about between 4 and 6.9,

and then incorporating with the paper and board between about 0.2% and 5% of finely ground cacao shells.

6. Antioxygenic paper and board containing the heat reaction products of the reaction between 0.2% and 5% of finely ground cacao shells and the paper and board, said reaction being obtained by heating the paper and board to at least about 220 F.

7. Antioxygenic paper and board containing between about 0.2% and 5% of finely ground cacao shells and having a pH of between about 4 and 6.9.

8. In the method of making antioxygenic paper and board, the steps of providing P per and board pulp having a pH of about between 4 and 6.9, and then incorporating with the paper and board pulp between about 0.2% and 5% of cacao residue.

9. Antioxygenic paper and board containing incorporated with the surface thereof between 8mm smsrma. 

